GameStop shares more than halved on Tuesday as losses piled up on stocks favoured by the army of day traders that have organised on the social media site Reddit.

The declines were so sharp that at one point they triggered a brief trading halt in GameStop and automatic curbs also kicked in to calm jittery trading in other stocks favoured by retail traders.

GameStop and others such as BlackBerry and AMC Entertainment have become synonymous with the new wave of day traders that have swept into US financial markets since the pandemic hit the country last year.

Last week’s rally in GameStop shares inflicted billions of dollars of losses for hedge funds who had bet the company’s shares would decline, prompting a bailout of star manager Gabe Plotkin’s Melvin Capital from Citadel and Point72 Asset Management.

But a Goldman Sachs index of US stocks targeted by short sellers dropped more than 7 per cent on Tuesday, suggesting hedge funds that have stuck with their negative bets were making money again and that the tide has turned in the battle with retail investors. The index is down 13 per cent from the high it struck last week.

GameStop was down as much as 67 per cent before noon in New York, and has now lost more than 80 per cent of its value from an intraday peak last week. Shares of AMC fell as much as 55 per cent on Tuesday, while BlackBerry was off 24 per cent at the lows of the day.

The declines have wiped roughly $27bn from the pumped-up valuations of the three companies.

Line chart of share price ($) showing GameStop shares have crashed

“This was bound to happen — it goes back to the age-old premise that the stock market ultimately at the fringes is driven by greed and fear,” said Mike Mullaney, director of global markets research at Boston Partners. “I feel badly for anybody who’s jumped on this trade in the last week, especially on the buy side.”

Traders on the Reddit message board r/WallStreetBets repeated the mantra to “hold the line”, telling other investors who had piled into AMC and GameStop not to sell. One rushed to offer support to other investors who claimed mounting losses, writing: “It’s not a loss until it’s realised.”

Silver, which had become another target of at least some retail investors, also pulled back sharply on Tuesday after a rally in the previous session. The precious metal dropped 7.7 per cent to $26.74 an ounce, having risen to an eight-year peak above $30 on Monday.

Regulators in Washington have sharpened their gaze on the volatile trading, which has often moved in sharp contrast to the broader market. The financial services committee of the House of Representatives has scheduled a hearing on the rally and crash in GameStop shares for later this month, including into why the popular trading app Robinhood restricted trading in some shares last week.

Robinhood said on Tuesday that it was easing some of the remaining restrictions, including raising the amount of GameStop shares its users could buy to 100, from just one on Monday.

David Giroux, chief investment officer for equity and multi-asset at T Rowe Price, noted that the most recent trading frenzy had parallels to the dotcom bubble roughly two decades ago.

“Parts of the market are going to be fine . . . but it is very concentrated where you see speculative excess,” he said.